Only access the HVM union b_info->u.hvm on HVM guests. The union
access is not guarded, so this reads and sets the default even on
non-HVM guests. Usually this doesn't matter as PV and PVH unions are
smaller and zero-initialized, but the zero default will be re-written as
a -1 boolean. Generally, it could incorrectly set b_info->altp2m
through aliased data.
Fixes: 0291089f6ea8 ("xen: enable altp2m at create domain domctl")
Signed-off-by: Jason Andryuk <jason.andr...@amd.com>
---
v2:
Move comment.
---
tools/libs/light/libxl_x86.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c
index 0b1c2d3a96..867addfcab 100644
--- a/tools/libs/light/libxl_x86.c
+++ b/tools/libs/light/libxl_x86.c
@@ -814,17 +814,19 @@ int libxl__arch_domain_build_info_setdefault(libxl__gc
*gc,
libxl_defbool_setdefault(&b_info->acpi, true);
libxl_defbool_setdefault(&b_info->arch_x86.msr_relaxed, false);
- /*
- * The config parameter "altp2m" replaces the parameter "altp2mhvm".
- * For legacy reasons, both parameters are accepted on x86 HVM guests.
- *
- * If the legacy field info->u.hvm.altp2m is set, activate altp2m.
- * Otherwise set altp2m based on the field info->altp2m.
- */
- libxl_defbool_setdefault(&b_info->u.hvm.altp2m, false);
- if (b_info->altp2m == LIBXL_ALTP2M_MODE_DISABLED &&
- libxl_defbool_val(b_info->u.hvm.altp2m))
- b_info->altp2m = libxl_defbool_val(b_info->u.hvm.altp2m);
+ if (b_info->type == LIBXL_DOMAIN_TYPE_HVM) {
+ /*
+ * The config parameter "altp2m" replaces the parameter "altp2mhvm".
+ * For legacy reasons, both parameters are accepted on x86 HVM guests.
+ *
+ * If the legacy field info->u.hvm.altp2m is set, activate altp2m.
+ * Otherwise set altp2m based on the field info->altp2m.
+ */
+ libxl_defbool_setdefault(&b_info->u.hvm.altp2m, false);
+ if (b_info->altp2m == LIBXL_ALTP2M_MODE_DISABLED &&
+ libxl_defbool_val(b_info->u.hvm.altp2m))
+ b_info->altp2m = libxl_defbool_val(b_info->u.hvm.altp2m);
+ }
return 0;
}
--
2.49.0
